Clinical characteristics and outcomes of patients with 2009 influenza A(H1N1) virus infection with respiratory failure requiring mechanical ventilation

Epidemiological investigation of lower respiratory tract infections during influenza A (H1N1) pdm09 virus pandemic based on targeted next-generation sequencing

Background

Co-infection has been a significant contributor to morbidity and mortality in previous influenza pandemics. However, the current influenza A (H1N1) pdm09 virus pandemic, as the first major outbreak following the SARS-CoV-2 pandemic, may differ epidemiologically. Further investigation is necessary to understand the specific features and impact of this influenza A pandemic. Study design: We conducted a retrospective cohort study at a Chinese hospital between January and April 2023, focusing on patients with lower respiratory tract infections. Pathogen detection employed targeted next-generation sequencing (tNGS) on bronchoalveolar lavage fluid (BALF) or sputum samples.

Results

This study enrolled 167 patients with lower respiratory tract infections, and the overall positivity rate detected through tNGS was around 80%. Among them, 40 patients had influenza A (H1N1) pdm09 virus infection, peaking in March. In these patients, 27.5% had sole infections, and 72.5% had co-infections, commonly with bacteria. The frequently detected pathogens were Aspergillus fumigatus, SARS-CoV-2, and Streptococcus pneumoniae. For non-influenza A virus-infected patients, the co-infection rate was 36.1%, with 42.3% having SARS-CoV-2. Patients with influenza A virus infection were younger, had more females and diabetes cases. Among them, those with sole infections were older, with less fever and asthma but more smoking history. Regarding prognosis, compared to sole influenza A virus infection, co-infected patients demonstrated higher 21-day recovery rates and a higher incidence of heart failure. However, they exhibited lower proportions of respiratory failure, acute kidney failure, septic shock, and hospital stays lasting more than 10 days. Interestingly, patients with non-influenza A virus infection had a significantly lower 21-day recovery rate. Correlation analysis indicated that the 21-day recovery rate was only associated with influenza A (H1N1) pdm09 virus.

Conclusion

During the current pandemic, the influenza A (H1N1) pdm09 virus may have been influenced by the SARS-CoV-2 pandemic and did not exhibit a strong pathogenicity. In fact, patients infected with influenza A virus showed better prognoses compared to those infected with other pathogens. Additionally, tNGS demonstrated excellent detection performance in this study and showed great potential, prompting clinical physicians to consider its use as an auxiliary diagnostic tool.

Prolonged exposure to lung-derived cytokines is associated with inflammatory activation of microglia in patients with COVID-19

Neurological impairment is the most common finding in patients with post-acute sequelae of COVID-19. Furthermore, survivors of pneumonia from any cause have an elevated risk of dementia1-4. Dysfunction in microglia, the primary immune cell in the brain, has been linked to cognitive impairment in murine models of dementia and in humans5. Here, we report a transcriptional response in human microglia collected from patients who died following COVID-19 suggestive of their activation by TNF-α and other circulating pro-inflammatory cytokines. Consistent with these findings, the levels of 55 alveolar and plasma cytokines were elevated in a cohort of 341 patients with respiratory failure, including 93 unvaccinated patients with COVID-19 and 203 patients with other causes of pneumonia. While peak levels of pro-inflammatory cytokines were similar in patients with pneumonia irrespective of etiology, cumulative cytokine exposure was higher in patients with COVID-19. Corticosteroid treatment, which has been shown to be beneficial in patients with COVID-196, was associated with lower levels of CXCL10, CCL8, and CCL2-molecules that sustain inflammatory circuits between alveolar macrophages harboring SARS-CoV-2 and activated T cells7. These findings suggest that corticosteroids may break this cycle and decrease systemic exposure to lung-derived cytokines and inflammatory activation of microglia in patients with COVID-19.

Influenza in patients with respiratory failure admitted to intensive care units in Poland and the use of extracorporeal respiratory support: a survey-based multicenter study

Background

In Poland, little is known about the most serious cases of influenza that need admittance to the intensive care unit (ICU), as well as the use of extracorporeal respiratory support.

Methods

This was an electronic survey comprising ICUs in two administrative regions of Poland. The aim of the study was to determine the number of influenza patients with respiratory failure admitted to the ICU in the autumn–winter season of 2018/2019. Furthermore, respiratory support, outcome and other pathogens detected in the airways were investigated.

Results

Influenza infection was confirmed in 76 patients. The A(H1N1)pdm09 strain was the most common. 34 patients died (44.7%). The median age was 62 years, the median sequential organ failure assessment (SOFA) score was 11 and was higher in patients who died (12 vs. 10, p = 0.017). Mechanical ventilation was used in 75 patients and high flow nasal oxygen therapy in 1 patient. Extracorporeal membrane oxygenation (ECMO) was used in 7 patients (6 survived), and extracorporeal carbon dioxide removal (ECCO₂R) in 2 (1 survived). The prone position was used in 16 patients. In addition, other pathogens were detected in the airways on admittance to the ICU.

Conclusion

A substantial number of influenza infections occurred in the autumn–winter season of 2018/2019 that required costly treatment in the intensive care units. Upon admission to the ICU, influenza patients had a high degree of organ failure as assessed by the SOFA score, and the mortality rate was 44.7%. Advanced extracorporeal respiratory techniques offer real survival opportunities to patients with severe influenza-related ARDS. The presence of coinfection should be considered in patients with influenza and respiratory failure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06672-w.

Distinctive features of severe SARS-CoV-2 pneumonia

The coronavirus disease 2019 (COVID-19) pandemic is among the most important public health crises of our generation. Despite the promise of prevention offered by effective vaccines, patients with severe COVID-19 will continue to populate hospitals and intensive care units for the foreseeable future. The most common clinical presentation of severe COVID-19 is hypoxemia and respiratory failure, typical of the acute respiratory distress syndrome (ARDS). Whether the clinical features and pathobiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia differ from those of pneumonia secondary to other pathogens is unclear. This uncertainty has created variability in the application of historically proven therapies for ARDS to patients with COVID-19. We review the available literature and find many similarities between patients with ARDS from pneumonia attributable to SARS-CoV-2 versus other respiratory pathogens. A notable exception is the long duration of illness among patients with COVID-19, which could result from its unique pathobiology. Available data support the use of care pathways and therapies proven effective for patients with ARDS, while pointing to unique features that might be therapeutically targeted for patients with severe SARS-CoV-2 pneumonia.

Outcomes of respiratory viral-bacterial co-infection in adult hospitalized patients

BACKGROUND

Viral infections of the respiratory tract represent a major global health concern. Co-infection with bacteria may contribute to severe disease and increased mortality in patients. Nevertheless, viral-bacterial co-infection patterns and their clinical outcomes have not been well characterized to date. This study aimed to evaluate the clinical features and outcomes of patients with viral-bacterial respiratory tract co-infections.

METHODS

We included 19,361 patients with respiratory infection due to respiratory viruses [influenza A and B, respiratory syncytial virus (RSV), parainfluenza] and/or bacteria in four tertiary hospitals in Hong Kong from 2013 to 2017 using a large territory-wide healthcare database. All microbiological tests were conducted within 48 h of hospital admission. Four etiological groups were included: (1) viral infection alone; (2) bacterial infection alone; (3) laboratory-confirmed viral-bacterial co-infection and (4) clinically suspected viral-bacterial co-infection who were tested positive for respiratory virus and negative for bacteria but had received at least four days of antibiotics. Clinical features and outcomes were recorded for laboratory-confirmed viral-bacterial co-infection patients compared to other three groups as control. The primary outcome was 30-day mortality. Secondary outcomes were intensive care unit (ICU) admission and length of hospital stay. Propensity score matching estimated by binary logistic regression was used to adjust for the potential bias that may affect the association between outcomes and covariates.

FINDINGS

Among 15,906 patients with respiratory viral infection, there were 8451 (53.1%) clinically suspected and 1,087 (6.8%) laboratory-confirmed viral-bacterial co-infection. Among all the bacterial species, Haemophilus influenzae (226/1,087, 20.8%), Pseudomonas aeruginosa (180/1087, 16.6%) and Streptococcus pneumoniae (123/1087, 11.3%) were the three most common bacterial pathogens in the laboratory-confirmed co-infection group. Respiratory viruses co-infected with non-pneumococcal streptococci or methicillin-resistant Staphylococcus aureus was associated with the highest death rate [9/30 (30%) and 13/48 (27.1%), respectively] in this cohort. Compared with other infection groups, patients with laboratory-confirmed co-infection had higher ICU admission rate (p < 0.001) and mortality rate at 30 days (p = 0.028), and these results persisted after adjustment for potential confounders using propensity score matching. Furthermore, patients with laboratory-confirmed co-infection had significantly higher mortality compared to patients with bacterial infection alone.

INTERPRETATION

In our cohort, bacterial co-infection is common in hospitalized patients with viral respiratory tract infection and is associated with higher ICU admission rate and mortality. Therefore, active surveillance for bacterial co-infection and early antibiotic treatment may be required to improve outcomes in patients with respiratory viral infection.

Myeloid dysregulation and therapeutic intervention in COVID-19

The dysregulation of myeloid cell responses is increasingly demonstrated to be a major mechanism of pathogenesis for COVID-19. The pathological cellular and cytokine signatures associated with this disease point to a critical role of a hyperactivated innate immune response in driving pathology. Unique immunopathological features of COVID-19 include myeloid-cell dominant inflammation and cytokine release syndrome (CRS) alongside lymphopenia and acute respiratory distress syndrome (ARDS), all of which correlate with severe disease. Studies suggest a range of causes mediating myeloid hyperactivation, such as aberrant innate sensing, asynchronized immune cellular responses, as well as direct viral protein/host interactions. These include the recent identification of new myeloid cell receptors that bind SARS-CoV-2, which drive myeloid cell hyperinflammatory responses independently of lung epithelial cell infection via the canonical receptor, angiotensin-converting enzyme 2 (ACE2). The spectrum and nature of myeloid cell dysregulation in COVID-19 also differs from, at least to some extent, what is observed in other infectious diseases involving myeloid cell activation. While much of the therapeutic effort has focused on preventative measures with vaccines or neutralizing antibodies that block viral infection, recent clinical trials have also targeted myeloid cells and the associated cytokines as a means to resolve CRS and severe disease, with promising but thus far modest effects. In this review, we critically examine potential mechanisms driving myeloid cell dysregulation, leading to immunopathology and severe disease, and discuss potential therapeutic strategies targeting myeloid cells as a new paradigm for COVID-19 treatment.

Clinical characteristics of SARS-CoV-2 infection in children with cystic fibrosis: An international observational study

BACKGROUND

The presence of co-morbidities, including underlying respiratory problems, has been identified as a risk factor for severe COVID-19 disease. Information on the clinical course of SARS-CoV-2 infection in children with cystic fibrosis (CF) is limited, yet vital to provide accurate advice for children with CF, their families, caregivers and clinical teams.

METHODS

Cases of SARS-CoV-2 infection in children with CF aged less than 18 years were collated by the CF Registry Global Harmonization Group across 13 countries between 1 February and 7 August 2020.

RESULTS

Data on 105 children were collated and analysed. Median age of cases was ten years (interquartile range 6-15), 54% were male and median percentage predicted forced expiratory volume in one second was 94% (interquartile range 79-104). The majority (71%) of children were managed in the community during their COVID-19 illness. Out of 24 children admitted to hospital, six required supplementary oxygen and two non-invasive ventilation. Around half were prescribed antibiotics, five children received antiviral treatments, four azithromycin and one additional corticosteroids. Children that were hospitalised had lower lung function and reduced body mass index Z-scores. One child died six weeks after testing positive for SARS-CoV-2 following a deterioration that was not attributed to COVID-19 disease.

CONCLUSIONS

SARS-CoV-2 infection in children with CF is usually associated with a mild illness in those who do not have pre-existing severe lung disease.

The Clinical Impact of Cirrhosis on the Hospital Outcomes of Patients Admitted With Influenza Infection: Propensity Score Matched Analysis of 2011-2017 US Hospital Data

BACKGROUND/OBJECTIVES

Patients with cirrhosis have liver-related immune dysfunction that potentially predisposes the patients to increased influenza infection risk. Our study evaluates this cross-sectional relationship using a national registry of hospital patients.

METHODS

This study included the 2011-2017 National Inpatient Sample database. From this, respiratory influenza cases were isolated and stratified using the presence of cirrhosis into a cirrhosis-present study cohort and cirrhosis-absent controls; propensity score matching method was used to match the controls to the study cohort (cirrhosis-present) using a 1:1 matching ratio. The endpoints included mortality, length of stay, hospitalization costs, and influenza-related complications.

RESULTS

Following the match, there were 2,040 with cirrhosis and matched 2,040 without cirrhosis admitted with respiratory influenza infection. Compared to the controls, cirrhosis patients had higher in-hospital mortality (7.79 vs 3.43% p < 0.001, OR 2.38 95% CI 1.78-3.17), longer length of stay (7.25 vs 6.52 d p < 0.001), higher hospitalization costs ($70,009 vs $65,035 p < 0.001), and were more likely be discharged to a skilled nursing facility and home healthcare (vs routine home discharges). In terms of influenza-related complications, the cirrhosis cohort had higher rates of sepsis (29.8 vs 22% p < 0.001, OR 1.51 95% CI 1.31-1.74). In the multivariate regression analysis, cirrhosis was associated with higher mortality (p < 0.001, aOR 2.31 95% CI 1.59-3.35) and length of stay (p = 0.018, aOR 1.03 95% CI 1.01-1.06). In subgroup analysis of patients with decompensated (n = 597) versus compensated cirrhosis (n = 1443), those with decompensated cirrhosis had higher rates of in-hospital mortality (12.7 vs 5.75% p < 0.001, OR 2.39 95% CI 1.72-3.32), length of stay (8.85 vs 6.59 d p < 0.001), and hospitalization costs ($92,858 vs $60,556 p < 0.001). In the multivariate analysis, decompensated cirrhosis was associated with increased mortality (p < 0.001, aOR 2.86 95% CI 1.90-4.32).

CONCLUSION

This study shows the presence of cirrhosis to result in higher hospital mortality and postinfluenza complications in patients with influenza infection.

Risk factors for non-invasive ventilation failure in influenza infection with acute respiratory failure in emergency department

OBJECTIVE

Non-invasive ventilation (NIV) has been widely used in hypoxemic acute respiratory failure (ARF) due to influenza pneumonia in the emergency department (ED). However, NIV used in influenza-associated acute respiratory failure had a variable rate of failure. Previous studies have reported that prolonged use of NIV was associated with increased mortality. Our study aimed to identify risk factors for NIV failure in influenza infection with acute respiratory failure in ED.

METHOD

We performed a retrospective cohort observational study. Enrolled patients were older than 18 years who used NIV due to influenza infection with ARF between 1 January 2017 to 31 December 2018 in Ramathibodi Emergency Department. Patients characteristics, comorbidity, clinical, laboratory outcome, chest imaging, initial NIV setting, and parameters were collected in ED setting. Sequential organ failure assessment (SOFA) score and PaO2/FiO2 (PF) ratio were calculated from the first arterial blood gas in ED. We followed the outcome success or failure of the NIV used.

RESULTS

A total of 162 patients were enrolled and 72 (44%) suffered NIV failure in influenza infection with ARF. We used univariate and multivariate logistic analyses to assess risk factors for NIV failure. The ability of risk factor to predict NIV failure was analyzed using the area under the receiver operating characteristic (AUROC). Risk factors of NIV failure included SOFA score (P = 0.001), PF ratio (P = 0.001) and quadrant infiltrations in chest x-rays (CXR) (P = 0.001). SOFA score, PF ratio, and number quadrant infiltrations in chest radiography have good ability to predict NIV failure, AUROC 0.894 (95%CI 0.839-0.948), 0.828 (95%CI 0.764-0.892), and 0.792 (95%CI 0.721-0.863), respectively and no significant difference in the ability to predict NIV failure among three parameters. The use of PF ratio plus number quadrant infiltrations in chest radiography demonstrated a higher predictive ability for NIV failure in influenza infection with ARF.

CONCLUSIONS

SOFA score, PF ratio, and quadrant infiltrations in chest radiography were good predictors of NIV failure in influenza infection with ARF.

Clinical consensus recommendations regarding non-invasive respiratory support in the adult patient with acute respiratory failure secondary to SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus, that was first recognized in Wuhan, China, in December 2019. Currently, the World Health Organization (WHO) has defined the infection as a global pandemic and there is a health and social emergency for the management of this new infection. While most people with COVID-19 develop only mild or uncomplicated illness, approximately 14% develop severe disease that requires hospitalization and oxygen support, and 5% require admission to an intensive care unit. In severe cases, COVID-19 can be complicated by the acute respiratory distress syndrome (ARDS), sepsis and septic shock, and multiorgan failure. This consensus document has been prepared on evidence-informed guidelines developed by a multidisciplinary panel of health care providers from four Spanish scientific societies (Spanish Society of Intensive Care Medicine [SEMICYUC], Spanish Society of Pulmonologists [SEPAR], Spanish Society of Emergency [SEMES], Spanish Society of Anesthesiology, Reanimation, and Pain [SEDAR]) with experience in the clinical management of patients with COVID-19 and other viral infections, including SARS, as well as sepsis and ARDS. The document provides clinical recommendations for the noninvasive respiratory support (noninvasive ventilation, high flow oxygen therapy with nasal cannula) in any patient with suspected or confirmed presentation of COVID-19 with acute respiratory failure.

This consensus guidance should serve as a foundation for optimized supportive care to ensure the best possible chance for survival and to allow for reliable comparison of investigational therapeutic interventions as part of randomized controlled trials.

Clinical Consensus Recommendations Regarding Non-Invasive Respiratory Support in the Adult Patient with Acute Respiratory Failure Secondary to SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus, that was first recognized in Wuhan, China, in December 2019. Currently, the World Health Organization (WHO) has defined the infection as a global pandemic and there is a health and social emergency for the management of this new infection. While most people with COVID-19 develop only mild or uncomplicated illness, approximately 14% develop severe disease that requires hospitalization and oxygen support, and 5% require admission to an intensive care unit. In severe cases, COVID-19 can be complicated by the acute respiratory distress syndrome (ARDS), sepsis and septic shock, and multiorgan failure. This consensus document has been prepared on evidence-informed guidelines developed by a multidisciplinary panel of health care providers from four Spanish scientific societies (Spanish Society of Intensive Care Medicine [SEMICYUC], Spanish Society of Pulmonologists [SEPAR], Spanish Society of Emergency [SEMES], Spanish Society of Anesthesiology, Reanimation, and Pain [SEDAR]) with experience in the clinical management of patients with COVID-19 and other viral infections, including SARS, as well as sepsis and ARDS. The document provides clinical recommendations for the noninvasive respiratory support (noninvasive ventilation, high flow oxygen therapy with nasal cannula) in any patient with suspected or confirmed presentation of COVID-19 with acute respiratory failure. This consensus guidance should serve as a foundation for optimized supportive care to ensure the best possible chance for survival and to allow for reliable comparison of investigational therapeutic interventions as part of randomized controlled trials.

Clinical consensus recommendations regarding non-invasive respiratory support in the adult patient with acute respiratory failure secondary to SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus, that was first recognized in Wuhan, China, in December 2019. Currently, the World Health Organization (WHO) has defined the infection as a global pandemic and there is a health and social emergency for the management of this new infection. While most people with COVID-19 develop only mild or uncomplicated illness, approximately 14% develop severe disease that requires hospitalization and oxygen support, and 5% require admission to an intensive care unit. In severe cases, COVID-19 can be complicated by the acute respiratory distress syndrome (ARDS), sepsis and septic shock, and multiorgan failure. This consensus document has been prepared on evidence-informed guidelines developed by a multidisciplinary panel of health care providers from four Spanish scientific societies (Spanish Society of Intensive Care Medicine [SEMICYUC], Spanish Society of Pulmonologists [SEPAR], Spanish Society of Emergency [SEMES], Spanish Society of Anesthesiology, Reanimation, and Pain [SEDAR]) with experience in the clinical management of patients with COVID-19 and other viral infections, including SARS, as well as sepsis and ARDS. The document provides clinical recommendations for the noninvasive respiratory support (noninvasive ventilation, high flow oxygen therapy with nasal cannula) in any patient with suspected or confirmed presentation of COVID-19 with acute respiratory failure.

This consensus guidance should serve as a foundation for optimized supportive care to ensure the best possible chance for survival and to allow for reliable comparison of investigational therapeutic interventions as part of randomized controlled trials.

[Clinical consensus recommendations regarding non-invasive respiratory support in the adult patient with acute respiratory failure secondary to SARS-CoV-2 infection]

La enfermedad por coronavirus 2019 (COVID-19) es una infección del tracto respiratorio causada por un nuevo coronavirus emergente que se reconoció por primera vez en Wuhan, China, en diciembre de 2019. Actualmente la Organización Mundial de la Salud (OMS) ha definido la infección como pandemia y existe una situación de emergencia sanitaria y social para el manejo de esta nueva infección. Mientras que la mayoría de las personas con COVID-19 desarrollan solo una enfermedad leve o no complicada, aproximadamente el 14% desarrollan una enfermedad grave que requiere hospitalización y oxígeno, y el 5% pueden requerir ingreso en una unidad de cuidados intensivos. En casos severos, COVID-19 puede complicarse por el síndrome de dificultad respiratoria aguda (SDRA), sepsis y shock séptico y fracaso multiorgánico. Este documento de consenso se ha preparado sobre directrices basadas en evidencia desarrolladas por un panel multidisciplinario de profesionales médicos de cuatro sociedades científicas españolas (Sociedad Española de Medicina Intensiva y Unidades Coronarias [SEMICYUC], Sociedad Española de Neumología y Cirugía Torácica [SEPAR], Sociedad Española de Urgencias y Emergencias [SEMES], Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor [SEDAR]) con experiencia en el manejo clínico de pacientes con COVID-19 y otras infecciones virales, incluido el SARS, así como en sepsis y SDRA. El documento proporciona recomendaciones clínicas para el soporte respiratorio no invasivo (ventilación no invasiva, oxigenoterapia de alto flujo con cánula nasal) en cualquier paciente con presentación sospechada o confirmada de COVID-19 con insuficiencia respiratoria aguda.

Esta guía de consenso debe servir como base para una atención optimizada y garantizar la mejor posibilidad de supervivencia, así como permitir una comparación fiable de las futuras intervenciones terapéuticas de investigación que formen parte de futuros estudios observacionales o de ensayos clínicos.

Clinical Consensus Recommendations Regarding Non-Invasive Respiratory Support in the Adult Patient with Acute Respiratory Failure Secondary to SARS-CoV-2 infection

La enfermedad por coronavirus 2019 (COVID-19) es una infección del tracto respiratorio causada por un nuevo coronavirus emergente que se reconoció por primera vez en Wuhan, China, en diciembre de 2019. Actualmente la Organización Mundial de la Salud (OMS) ha definido la infección como pandemia y existe una situación de emergencia sanitaria y social para el manejo de esta nueva infección. Mientras que la mayoría de las personas con COVID-19 desarrollan solo una enfermedad leve o no complicada, aproximadamente el 14% desarrollan una enfermedad grave que requiere hospitalización y oxígeno, y el 5% pueden requerir ingreso en una Unidad de Cuidados Intensivos. En casos severos, COVID-19 puede complicarse por el síndrome de dificultad respiratoria aguda (SDRA), sepsis y shock séptico y fracaso multiorgánico. Este documento de consenso se ha preparado sobre directrices basadas en evidencia desarrolladas por un panel multidisciplinario de profesionales médicos de cuatro sociedades científicas españolas (Sociedad Española de Medicina Intensiva y Unidades Coronarias [SEMICYUC], Sociedad Española de Neumología y Cirugía Torácica [SEPAR], Sociedad Española de Urgencias y Emergencias [SEMES], Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor [SEDAR]) con experiencia en el manejo clínico de pacientes con COVID-19 y otras infecciones virales, incluido el SARS, así como en sepsis y SDRA. El documento proporciona recomendaciones clínicas para el soporte respiratorio no invasivo (ventilación no invasiva, oxigenoterapia de alto flujo con cánula nasal) en cualquier paciente con presentación sospechada o confirmada de COVID-19 con insuficiencia respiratoria aguda.

Esta guía de consenso debe servir como base para una atención optimizada y garantizar la mejor posibilidad de supervivencia, así como permitir una comparación fiable de las futuras intervenciones terapéuticas de investigación que formen parte de futuros estudios observacionales o de ensayos clínicos.

Novel Coronavirus 2019 (2019-nCoV) Infection: Part II - Respiratory Support in the Pediatric Intensive Care Unit in Resource-limited Settings

The 2019-novel coronavirus predominantly affects the respiratory system with manifestations ranging from upper respiratory symptoms to full blown acute respiratory distress syndrome (ARDS). It is important to recognize the risk factors, categorize severity and provide early treatment. Use of high flow devices and non-invasive ventilation has been discouraged due to high chances of aerosol generation. Early intubation and mechanical ventilation areessential to prevent complications and worsening, especially in resource-limited settings with very few centers having expertise to manage critical cases. Hydrophobic viral filter in the ventilator circuit minimizes chances of transmission of virus. Strategies to manage ARDS in COVID-19 include low tidal volume ventilation with liberal sedation-analgesia. At the same time, prevention of transmission of the virus to healthcare workers is extremely important in the intensive care setting dealing with severe cases and requiring procedures generating aerosol. We, herein, provide guidance on non-invasive respiratory support, intubation and management of ARDS in a child with COVID-19.

Metabolomic Profile of ARDS by Nuclear Magnetic Resonance Spectroscopy in Patients With H1N1 Influenza Virus Pneumonia

PURPOSE

The integrated analysis of changes in the metabolic profile could be critical for the discovery of biomarkers of lung injury, and also for generating new pathophysiological hypotheses and designing novel therapeutic targets for the acute respiratory distress syndrome (ARDS). This study aimed at developing a nuclear magnetic resonance (NMR)-based approach for the identification of the metabolomic profile of ARDS in patients with H1N1 influenza virus pneumonia.

METHODS

Serum samples from 30 patients (derivation set) diagnosed of H1N1 influenza virus pneumonia were analyzed by unsupervised principal component analysis to identify metabolic differences between patients with and without ARDS by NMR spectroscopy. A predictive model of partial least squares discriminant analysis (PLS-DA) was developed for the identification of ARDS. PLS-DA was trained with the derivation set and tested in another set of samples from 26 patients also diagnosed of H1N1 influenza virus pneumonia (validation set).

RESULTS

Decreased serum glucose, alanine, glutamine, methylhistidine and fatty acids concentrations, and elevated serum phenylalanine and methylguanidine concentrations, discriminated patients with ARDS versus patients without ARDS. PLS-DA model successfully identified the presence of ARDS in the validation set with a success rate of 92% (sensitivity 100% and specificity 91%). The classification functions showed a good correlation with the Sequential Organ Failure Assessment score (R = 0.74, P < 0.0001) and the PaO2/FiO2 ratio (R = 0.41, P = 0.03).

CONCLUSIONS

The serum metabolomic profile is sensitive and specific to identify ARDS in patients with H1N1 influenza A pneumonia. Future studies are needed to determine the role of NMR spectroscopy as a biomarker of ARDS.

Investing in antibiotics to alleviate future catastrophic outcomes: What is the value of having an effective antibiotic to mitigate pandemic influenza?

Over 95% of post-mortem samples from the 1918 pandemic, which caused 50 to 100 million deaths, showed bacterial infection complications. The introduction of antibiotics in the 1940s has since reduced the risk of bacterial infections, but growing resistance to antibiotics could increase the toll from future influenza pandemics if secondary bacterial infections are as serious as in 1918, or even if they are less severe. We develop a valuation model of the option to withhold wide use of an antibiotic until significant outbreaks such as pandemic influenza or foodborne diseases are identified. Using real options theory, we derive conditions under which withholding wide use is beneficial, and calculate the option value for influenza pandemic scenarios that lead to secondary infections with a resistant Staphylococcus aureus strain. We find that the value of withholding an effective novel oral antibiotic can be positive and significant unless the pandemic is mild and causes few secondary infections with the resistant strain or if most patients can be treated intravenously. Although the option value is sensitive to parameter uncertainty, our results suggest that further analysis on a case-by-case basis could guide investment in novel agents as well as strategies on how to use them.

Management of Acute Respiratory Failure Due to Community-Acquired Pneumonia: A Systematic Review

Community-acquired pneumonia (CAP) is a leading cause of mortality worldwide. CAP mortality is driven by the development of sepsis and acute respiratory failure (ARF). We performed a systematic review of the available English literature published in the period 1 January 1997 to 31 August 2017 and focused on ARF in CAP. The database searches identified 189 articles—of these, only 29 were retained for data extraction. Of these 29 articles, 12 addressed ARF in CAP without discussing its ventilatory management, while 17 evaluated the ventilatory management of ARF in CAP. In the studies assessing the ventilatory management, the specific treatments addressed were: high-flow nasal cannula (HFNC) (n = 1), continuous positive airway pressure (n = 2), non-invasive ventilation (n = 9), and invasive mechanical ventilation (n = 5). When analyzed, non-invasive ventilation (NIV) success rates ranged from 20% to 76% and they strongly predicted survival, while NIV failure led to an increased risk of adverse outcome. In conclusion, ARF in CAP patients may require both ventilatory and non-ventilatory management. Further research is needed to better evaluate the use of NIV and HFNC in those patients. Alongside the prompt administration of antimicrobials, the potential use of steroids and the implementation of severity scores should also be considered.

The role of pneumonia and secondary bacterial infection in fatal and serious outcomes of pandemic influenza a(H1N1)pdm09

BACKGROUND

The aim of this study was to estimate the prevalence of pneumonia and secondary bacterial infections during the pandemic of influenza A(H1N1)pdm09.

METHODS

A systematic review was conducted to identify relevant literature in which clinical outcomes of pandemic influenza A(H1N1)pdm09 infection were described. Published studies (between 01/01/2009 and 05/07/2012) describing cases of fatal or hospitalised A(H1N1)pdm09 and including data on bacterial testing or co-infection.

RESULTS

Seventy five studies met the inclusion criteria. Fatal cases with autopsy specimen testing were reported in 11 studies, in which any co-infection was identified in 23% of cases (Streptococcus pneumoniae 29%). Eleven studies reported bacterial co-infection among hospitalised cases of A(H1N1)2009pdm with confirmed pneumonia, with a mean of 19% positive for bacteria (Streptococcus pneumoniae 54%). Of 16 studies of intensive care unit (ICU) patients, bacterial co-infection identified in a mean of 19% of cases (Streptococcus pneumoniae 26%). The mean prevalence of bacterial co-infection was 12% in studies of hospitalised patients not requiring ICU (Streptococcus pneumoniae 33%) and 16% in studies of paediatric patients hospitalised in general or pediatric intensive care unit (PICU) wards (Streptococcus pneumoniae 16%).

CONCLUSION

We found that few studies of the 2009 influenza pandemic reported on bacterial complications and testing. Of studies which did report on this, secondary bacterial infection was identified in almost one in four patients, with Streptococcus pneumoniae the most common bacteria identified. Bacterial complications were associated with serious outcomes such as death and admission to intensive care. Prevention and treatment of bacterial secondary infection should be an integral part of pandemic planning, and improved uptake of routine pneumococcal vaccination in adults with an indication may reduce the impact of a pandemic.

Decision-making Process by Users and Providers of Health Care Services During the AH1N1 Epidemic Influenza in Mexico: Lessons Learned and Challenges Ahead

OBJECTIVE

The aim of the study was to analyze, using a decision analysis approach, the probability of severity of illness due to delayed utilization of health services and inappropriate hospital medical treatment during the 2009 AH1N1 influenza epidemic in Mexico.

METHODS

Patients with influenza AH1N1 confirmed by the polymerase chain reaction (PCR) test from two hospitals in Mexico City, were included. Path methodology based upon literature and validated by clinical experts was followed. The probability for severe illness originated from delayed utilization of health services, delayed prescription of neuraminidase inhibitors (NAIs) and inappropriate use of antibiotics was assessed.

FINDINGS

Ninety-nine patients were analyzed, and 16% developed severe illness. Most patients received NAIs and 85.9% received antibiotics. Inappropriate use of antibiotics was observed in 70.7% of cases. Early utilization of services increased the likelihood of non-severe illness (cumulative probability CP = 0.56). The major cumulative probability for severe illness was observed when prescription of NAIs was delayed (CP = 0.19).

CONCLUSION

Delayed prescription of NAIs and irrational use of antibiotics are critical decisions for unfavorable outcomes in patients suffering influenza AH1N1.

Bacterial and viral co-infections complicating severe influenza: Incidence and impact among 507 U.S. patients, 2013-14

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22.5% of adult patients with H1N1 developed bacterial co-infection.

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Staphylococcus aureus was the most common cause of co-infection.

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Bacterial and viral co-infections were associated with death in bivariate.

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Patients with a bacterial co-infection had greater use of resources.

Background

Influenza acts synergistically with bacterial co-pathogens. Few studies have described co-infection in a large cohort with severe influenza infection.

Objectives

To describe the spectrum and clinical impact of co-infections.

Study design

Retrospective cohort study of patients with severe influenza infection from September 2013 through April 2014 in intensive care units at 33 U.S. hospitals comparing characteristics of cases with and without co-infection in bivariable and multivariable analysis.

Results

Of 507 adult and pediatric patients, 114 (22.5%) developed bacterial co-infection and 23 (4.5%) developed viral co-infection. Staphylococcus aureus was the most common cause of co-infection, isolated in 47 (9.3%) patients. Characteristics independently associated with the development of bacterial co-infection of adult patients in a logistic regression model included the absence of cardiovascular disease (OR 0.41 [0.23–0.73], p = 0.003), leukocytosis (>11 K/μl, OR 3.7 [2.2–6.2], p < 0.001; reference: normal WBC 3.5–11 K/μl) at ICU admission and a higher ICU admission SOFA score (for each increase by 1 in SOFA score, OR 1.1 [1.0–1.2], p = 0.001). Bacterial co-infections (OR 2.2 [1.4–3.6], p = 0.001) and viral co-infections (OR 3.1 [1.3–7.4], p = 0.010) were both associated with death in bivariable analysis. Patients with a bacterial co-infection had a longer hospital stay, a longer ICU stay and were likely to have had a greater delay in the initiation of antiviral administration than patients without co-infection (p < 0.05) in bivariable analysis.

Conclusions

Bacterial co-infections were common, resulted in delay of antiviral therapy and were associated with increased resource allocation and higher mortality.

Relationship Between Upper Respiratory Tract Influenza Test Result and Clinical Outcomes Among Critically Ill Influenza Patients

Among critically ill patients with lower respiratory tract (LRT)-confirmed influenza, we retrospectively observed worse 28-day clinical outcomes in upper respiratory tract (URT)-negative versus URT-positive subjects. This finding may reflect disease progression and highlights the need for influenza testing of both URT and LRT specimens to improve diagnostic yield and possibly inform prognosis.

Noninvasive mechanical ventilation in high-risk pulmonary infections: a clinical review

The aim of this article was to review the role of noninvasive ventilation (NIV) in acute pulmonary infectious diseases, such as severe acute respiratory syndrome (SARS), H1N1 and tuberculosis, and to assess the risk of disease transmission with the use of NIV from patients to healthcare workers. We performed a clinical review by searching Medline and EMBASE. These databases were searched for articles on "clinical trials" and "randomised controlled trials". The keywords selected were non-invasive ventilation pulmonary infections, influenza-A (H1N1), SARS and tuberculosis. These terms were cross-referenced with the following keywords: health care workers, airborne infections, complications, intensive care unit and pandemic. The members of the International NIV Network examined the major results regarding NIV applications and SARS, H1N1 and tuberculosis. Cross-referencing mechanical ventilation with SARS yielded 76 studies, of which 10 studies involved the use of NIV and five were ultimately selected for inclusion in this review. Cross-referencing with H1N1 yielded 275 studies, of which 27 involved NIV. Of these, 22 were selected for review. Cross-referencing with tuberculosis yielded 285 studies, of which 15 involved NIV and from these seven were selected. In total 34 studies were selected for this review. NIV, when applied early in selected patients with SARS, H1N1 and acute pulmonary tuberculosis infections, can reverse respiratory failure. There are only a few reports of infectious disease transmission among healthcare workers.

A retrospective evaluation of critically ill patients infected with H1N1 influenza A virus in Bursa, Turkey, during the 2009-2010 pandemic

BACKGROUND

H1N1 influenza A virus infections were first reported in April 2009 and spread rapidly, resulting in mortality worldwide. The aim of this study was to evaluate patients with H1N1 infection treated in the intensive care unit (ICU) in Bursa, Turkey.

METHODS

Demographic characteristics, clinical features, and outcome relating to H1N1 infection were retrospectively analysed in patients treated in the ICU.

RESULTS

Twenty-three cases of H1N1 infection were treated in the ICU. The mean age of patients was 37 years range: (17-82). Fifteen patients were female (65.2%). The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 19 range: (5-39). The most common symptoms were dyspnea (73.9%), fever (69.6%), and cough (60.9%). Mechanical ventilation was required for all patients. Oseltamivir and antibiotics were administered to all patients. Six (26.1%) patients died. APACHE II scores were higher in the deceased 28.5 range: [16-39] vs. 14 range: [5-28] in survivors; p = 0.013).

CONCLUSION

When compared to the literature, the demographic, epidemiological, and clinical characteristics were similar in the cases we encountered. The mortality rate was high despite the use of appropriate treatment. We believe that the high mortality is related to higher APACHE II scores. The H1N1 virus should be considered in community acquired pneumonia, especially in younger patients presenting with severe pneumonia.

Do corticosteroids reduce the mortality of influenza A (H1N1) infection? A meta-analysis

Introduction

Corticosteroids are used empirically in influenza A (H1N1) treatment despite lack of clear evidence for effective treatment. This study aims to assess the efficacy of corticosteroids treatment for H1N1 infection.

Methods

Systematic review and meta-analysis were used to estimate the efficacy of corticosteroids for the prevention of mortality in H1N1 infection. Databases searched included MEDLINE, EMBASE, PubMed, Cochrane Central Register of Controlled Clinical Trials and so on, and bibliographies of retrieved articles, from April 2009 to October 2014. We included both cohort studies and case-control studies reported in English or Chinese that compared treatment effects between corticosteroids and non-corticosteroids therapy in inpatients with H1N1 virus infection. Cohort studies employed mortality as outcome, and case-control studies employed deaths as cases and survivors as controls; both were assessed in this meta-analysis.

Results

In total twenty-three eligible studies were included. Both cohort studies (nine studies, n = 1,405) and case-control studies (14 studies, n = 4,700) showed a similar trend toward increased mortality (cohort studies relative risk was 1.85 with 95% confidence interval (CI) 1.46 to 2.33; case-control studies odds ratio was 4.22 with 95% CI 3.10 to 5.76). The results from both subgroup analyses and sensitive analyses were consistent with each other, showing that steroid treatment is associated with mortality. However, considering the fact that corticosteroids were tend to be used in sickest case-patients and heterogeneity was observed between studies, we cannot make a solid conclusion.

Conclusions

Available evidence did not support the use of corticosteroids as standard care for patients with severe influenza. We conclude that further research is required.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0764-5) contains supplementary material, which is available to authorized users.

Influenza and endemic viral pneumonia

Viruses are a common and important cause of severe community-acquired pneumonia, and may lead to severe respiratory disease and admission to the intensive care unit. Influenza is the most common virus associated with severe viral pneumonia, although other important causes include respiratory syncytial virus, adenovirus, metapneumonia virus, and coronaviruses. Viral pneumonias tend to have a seasonal predilection and are often preceded by a typical viral prodrome. This article focuses on severe influenza pneumonia, including the 2009 H1N1 pandemic, and briefly discusses other causes of severe respiratory disease of viral etiology.

Ventilatory Strategy Used for Management of Acute Respiratory Failure Due to Novel Influenza A(H1N1) Infection

The first cases of the novel influenza A(H1N1) virus were reported in April 2009, especially in Mexico and the United States [1, 2]. The disease spread rapidly, becoming a pandemic by June 2009. On August 21, 2009, a total of 177 reported cases of novel influenza 182.166 A(H1N1) infection, of which 1,799 were fatal [2]. It has been observed in animal studies that the novel influenza virus A has a high replication rate in lung tissue, with a great capacity to invade the lower respiratory tract in humans, causing especially acute fulminant respiratory failure.

Noninvasive Mechanical Ventilation for Hypoxemic Respiratory Failure-Related Infectious Diseases

The strict range of applicability of noninvasive ventilation (NIV)—which had been applied only to patients with an exacerbation of chronic obstructive pulmonary disease (COPD) or acute cardiogenic pulmonary edema (ACPO)—has been extended during the last two decades.

Noninvasive Mechanical Ventilation in Patients with High-Risk Infections and Mass Casualties in Acute Respiratory Failure: Pediatric Perspective

Respiratory problems are common symptoms in children and common reason for visits to the pediatric emergency department (PED) and admission to the pediatric intensive care unit (PICU). Although the great majority of cases are benign and self-limited, requiring no intervention, some patients need respiratory support. Invasive mechanical ventilation (IMV) is a critical intervention in many cases of acute respiratory failure (ARF), but there are absolute risks associated with endotracheal intubation (ETI). On the other hand, noninvasive ventilation (NIV) is an extremely valuable alternative to IMV. A major reason for the increasing use of NIV has been the desire to avoid the complications of IMV. It is generally much safer than IMV and has been shown to decrease resource utilization. Its use also avoids the complications and side effects associated with ETI, including upper airway trauma, laryngeal swelling, postextubation vocal cord dysfunction, nosocomial infections, and ventilator-associated pneumonia. There are a number of advantages of NIV including leaving the upper airway intact, preserving the natural defense mechanisms of the upper airways, decreasing the need for sedation, maintaining the ability to talk while undergoing NIV, and reducing the length of hospitalization and its associated costs [1–3].

Safety and pharmacokinetics of intravenous zanamivir treatment in hospitalized adults with influenza: an open-label, multicenter, single-arm, phase II study

Background. Intravenous zanamivir is a neuraminidase inhibitor suitable for treatment of hospitalized patients with severe influenza.

Methods. Patients were treated with intravenous zanamivir 600 mg twice daily, adjusted for renal impairment, for up to 10 days. Primary outcomes included adverse events (AEs), and clinical/laboratory parameters. Pharmacokinetics, viral load, and disease course were also assessed.

Results. One hundred thirty patients received intravenous zanamivir (median, 5 days; range, 1–11) a median of 4.5 days (range, 1–7) after onset of influenza; 83% required intensive care. The most common influenza type/subtype was A/H1N1pdm09 (71%). AEs and serious AEs were reported in 85% and 34% of patients, respectively; serious AEs included bacterial pulmonary infections (8%), respiratory failure (7%), sepsis or septic shock (5%), and cardiogenic shock (5%). No drug-related trends in safety parameters were identified. Protocol-defined liver events were observed in 13% of patients. The 14- and 28-day all-cause mortality rates were 13% and 17%. No fatalities were considered zanamivir related. Pharmacokinetic data showed dose adjustments for renal impairment yielded similar zanamivir exposures. Ninety-three patients, positive at baseline for influenza by quantitative polymerase chain reaction, showed a median decrease in viral load of 1.42 log₁₀ copies/mL after 2 days of treatment.

Conclusions. Safety, pharmacokinetic and clinical outcome data support further investigation of intravenous zanamivir.

Clinical Trials Registration NCT01014988.

Non-invasive ventilation in critical care

Non-invasive ventilation refers to a number of respiratory support strategies commonly used in critical care settings. This paper describes the principles of non-invasive ventilation, the practicalities of its use and the evidence for its use in a number of common acute conditions.

Characteristics and outcome of mechanically ventilated patients with 2009 H1N1 influenza in Bosnia and Herzegovina and Serbia: impact of newly established multidisciplinary intensive care units

Aim

To describe characteristics and outcome of mechanically ventilated patients admitted to three newly established intensive care units (ICU) in Bosnia-Herzegovina and Serbia for 2009 H1N1 influenza infection.

Methods

The retrospective observational study included all mechanically ventilated adult patients of three university-affiliated hospitals between November 1^, 2009 and March 1 2010 who had 2009 H1N1 influenza infection confirmed by real-time reverse transcriptase-polymerase-chain-reaction (RT-PCR) from nasopharyngeal swab specimens and respiratory secretions.

Results

The study included 50 patients, 31 male (62%), aged 43 ± 13 years. Median time from hospital to ICU admission was 1 day (range 1-2). Sixteen patients (30%) presented with one or more chronic medical condition: 8 (16%) with chronic lung disease, 5 (10%) with chronic heart failure, and 3 (6%) with diabetes mellitus. Thirty-two (64%) were obese. Forty-eight patients (96%) experienced acute respiratory distress syndrome (ARDS), 28 (56%) septic shock, and 27 (54%) multiorgan failure. Forty-five patients (90%) were intubated and mechanically ventilated, 5 received non-invasive mechanical ventilation, 7 (14%) high-frequency oscillatory ventilation, and 7 (14%) renal replacement therapy. The median duration of mechanical ventilation was 7 (4-14) days. Hospital mortality was 52%.

Enhanced Tim3 activity improves survival after influenza infection

Influenza is a major cause of morbidity and mortality in the United States. Studies have shown that excessive T cell activity can mediate pneumonitis in the setting of influenza infection, and data from the 2009 H1N1 pandemic indicate that critical illness and respiratory failure postinfection were associated with greater infiltration of the lungs with CD8+ T cells. T cell Ig and mucin domain 3 (Tim3) is a negative regulator of Th1/Tc1-type immune responses. Activation of Tim3 on effector T cells has been shown to downregulate proliferation, cell-mediated cytotoxicity, and IFN-γ production, as well as induce apoptosis. In this article, we demonstrate that deletion of the terminal cytoplasmic domain of the Tim3 gene potentiates its ability to downregulate Tc1 inflammation, and that this enhanced Tim3 activity is associated with decreased phosphorylation of the TCR-CD3ζ-chain. We then show that mice with this Tim3 mutation infected with influenza are protected from morbidity and mortality without impairment in viral clearance or functional heterotypic immunity. This protection is associated with decreased CD8+ T cell proliferation and decreased production of inflammatory cytokines, including IFN-γ. Furthermore, the Tim3 mutation was protective against mortality in a CD8+ T cell-specific model of pneumonitis. These data suggest that Tim3 could be targeted to prevent immunopathology during influenza infection and demonstrate a potentially novel signaling mechanism used by Tim3 to downregulate the Tc1 response.

Bacterial co-infection with H1N1 infection in patients admitted with community acquired pneumonia

BACKGROUND

Bacterial co-infection is an important contributor to morbidity and mortality during influenza pandemics .We investigated the incidence, risk factors and outcome of patients with influenza A H1N1 pneumonia and bacterial co-infection.

METHODS

Prospective observational study of consecutive hospitalized patients with influenza A H1N1 virus and community-acquired pneumonia (CAP). We compared cases with and without bacterial co-infection.

RESULTS

The incidence of influenza A H1N1 infection in CAP during the pandemic period was 19% (n, 667). We studied 128 patients; 42(33%) had bacterial co-infection. The most frequently isolated bacterial pathogens were Streptococcus pneumoniae (26, 62%) and Pseudomonas aeruginosa (6, 14%). Predictors for bacterial co-infection were chronic obstructive pulmonary disease (COPD) and increase of platelets count. The hospital mortality was 9%. Factors associated with mortality were age ≥ 65 years, presence of septic shock and the need for mechanical ventilation. Although patients with bacterial co-infection presented with higher Pneumonia Severity Index risk class, hospital mortality was similar to patients without bacterial co-infection (7% vs. 11%, respectively, p = 0.54).

CONCLUSION

Bacterial co-infection was frequent in influenza A H1N1 pneumonia, with COPD and increased platelet count as the main predictors. Although associated with higher severe scales at admission, bacterial co-infection did not influence mortality of these patients.

An analysis of 332 fatalities infected with pandemic 2009 influenza A (H1N1) in Argentina

BACKGROUND

The apparent high number of deaths in Argentina during the 2009 pandemic led to concern that the influenza A H1N1pdm disease was different there. We report the characteristics and risk factors for influenza A H1N1pdm fatalities.

METHODS

We identified laboratory-confirmed influenza A H1N1pdm fatalities occurring during June-July 2009. Physicians abstracted data on age, sex, time of onset of illness, medical history, clinical presentation at admission, laboratory, treatment, and outcomes using standardize questionnaires. We explored the characteristics of fatalities according to their age and risk group.

RESULTS

Of 332 influenza A H1N1pdm fatalities, 226 (68%) were among persons aged <50 years. Acute respiratory failure was the leading cause of death. Of all cases, 249 (75%) had at least one comorbidity as defined by Advisory Committee on Immunization Practices. Obesity was reported in 32% with data and chronic pulmonary disease in 28%. Among the 40 deaths in children aged <5 years, chronic pulmonary disease (42%) and neonatal pathologies (35%) were the most common co-morbidities. Twenty (6%) fatalities were among pregnant or postpartum women of which only 47% had diagnosed co-morbidities. Only 13% of patients received antiviral treatment within 48 hours of symptom onset. None of children aged <5 years or the pregnant women received antivirals within 48 h of symptom onset. As the pandemic progressed, the time from symptom-onset to medical care and to antiviral treatment decreased significantly among case-patients who subsequently died (p<0.001).

CONCLUSION

Persons with co-morbidities, pregnant and who received antivirals late were over-represented among influenza A H1N1pdm deaths in Argentina, though timeliness of antiviral treatment improved during the pandemic.

Portable miniaturized extracorporeal membrane oxygenation systems for H1N1-related severe acute respiratory distress syndrome: a case series

BACKGROUND

Technological advances improved the practice of "modern" extracorporeal membrane oxygenation (ECMO). In the present report, we describe the experience of a referral ECMO center using portable miniaturized ECMO systems for H1N1-related severe acute respiratory distress syndrome (ARDS).

METHODS

An observational study of all patients with H1N1-associated ARDS treated with ECMO in Hospital S. João (Porto, Portugal) between November 2009 and April 2011 was performed. Extracorporeal membrane oxygenation support was established using either ELS or Cardiohelp systems (Maquet-Cardiopulmonary-AG, Hirrlingen, Germany).

RESULTS

Ten adult patients with severe ARDS secondary to H1N1 infection (Pao(2)/fraction of inspired oxygen, 69 mm Hg [56-84]; Murray score, 3.5 [3.5-3.8]) were included, and 60% survived to hospital discharge. Five patients were uneventfully transferred on ECMO from referring hospitals to our center by ambulance. Six patients were treated during the first postpandemic influenza season. All patients were treated with oseltamivir, and 1 received in addition zanamivir. Four patients received corticosteroids. Nosocomial infection was the most common complication (40%). Of the 4 deaths, 2 were caused by hemorrhagic shock; 1, by irreversible multiple organ failure; and 1, by refractory septic shock.

CONCLUSION

In our experience, ECMO support was a valuable therapeutic option for H1N1-related severe ARDS. The use of portable miniaturized systems allowed urgent rescue of patients from referring hospitals and safe interhospital and intrahospital transport during ECMO support.

[Recommendations of the Infectious Diseases Work Group (GTEI) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) and the Infections in Critically Ill Patients Study Group (GEIPC) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) for the diagnosis and treatment of influenza A/H1N1 in seriously ill adults admitted to the Intensive Care Unit]

The diagnosis of influenza A/H1N1 is mainly clinical, particularly during peak or seasonal flu outbreaks. A diagnostic test should be performed in all patients with fever and flu symptoms that require hospitalization. The respiratory sample (nasal or pharyngeal exudate or deeper sample in intubated patients) should be obtained as soon as possible, with the immediate start of empirical antiviral treatment. Molecular methods based on nucleic acid amplification techniques (RT-PCR) are the gold standard for the diagnosis of influenza A/H1N1. Immunochromatographic methods have low sensitivity; a negative result therefore does not rule out active infection. Classical culture is slow and has low sensitivity. Direct immunofluorescence offers a sensitivity of 90%, but requires a sample of high quality. Indirect methods for detecting antibodies are only of epidemiological interest. Patients with A/H1N1 flu may have relative leukopenia and elevated serum levels of LDH, CPK and CRP, but none of these variables are independently associated to the prognosis. However, plasma LDH> 1500 IU/L, and the presence of thrombocytopenia <150 x 10(9)/L, could define a patient population at risk of suffering serious complications. Antiviral administration (oseltamivir) should start early (<48 h from the onset of symptoms), with a dose of 75 mg every 12h, and with a duration of at least 7 days or until clinical improvement is observed. Early antiviral administration is associated to improved survival in critically ill patients. New antiviral drugs, especially those formulated for intravenous administration, may be the best choice in future epidemics. Patients with a high suspicion of influenza A/H1N1 infection must continue with antiviral treatment, regardless of the negative results of initial tests, unless an alternative diagnosis can be established or clinical criteria suggest a low probability of influenza. In patients with influenza A/H1N1 pneumonia, empirical antibiotic therapy should be provided due to the possibility of bacterial coinfection. A beta-lactam plus a macrolide should be administered as soon as possible. The microbiological findings and clinical or laboratory test variables may decide withdrawal or not of antibiotic treatment. Pneumococcal vaccination is recommended as a preventive measure in the population at risk of suffering severe complications. Although the use of moderate- or low-dose corticosteroids has been proposed for the treatment of influenza A/H1N1 pneumonia, the existing scientific evidence is not sufficient to recommend the use of corticosteroids in these patients. The treatment of acute respiratory distress syndrome in patients with influenza A/H1N1 must be based on the use of a protective ventilatory strategy (tidal volume <10 ml / kg and plateau pressure <35 mmHg) and positive end-expiratory pressure set to high patient lung mechanics, combined with the use of prone ventilation, muscle relaxation and recruitment maneuvers. Noninvasive mechanical ventilation cannot be considered a technique of choice in patients with acute respiratory distress syndrome, though it may be useful in experienced centers and in cases of respiratory failure associated with chronic obstructive pulmonary disease exacerbation or heart failure. Extracorporeal membrane oxygenation is a rescue technique in refractory acute respiratory distress syndrome due to influenza A/H1N1 infection. The scientific evidence is weak, however, and extracorporeal membrane oxygenation is not the technique of choice. Extracorporeal membrane oxygenation will be advisable if all other options have failed to improve oxygenation. The centralization of extracorporeal membrane oxygenation in referral hospitals is recommended. Clinical findings show 50-60% survival rates in patients treated with this technique. Cardiovascular complications of influenza A/H1N1 are common. Such problems may appear due to the deterioration of pre-existing cardiomyopathy, myocarditis, ischemic heart disease and right ventricular dysfunction. Early diagnosis and adequate monitoring allow the start of effective treatment, and in severe cases help decide the use of circulatory support systems. Influenza vaccination is recommended for all patients at risk. This indication in turn could be extended to all subjects over 6 months of age, unless contraindicated. Children should receive two doses (one per month). Immunocompromised patients and the population at risk should receive one dose and another dose annually. The frequency of adverse effects of the vaccine against A/H1N1 flu is similar to that of seasonal flu. Chemoprophylaxis must always be considered a supplement to vaccination, and is indicated in people at high risk of complications, as well in healthcare personnel who have been exposed.

Epidemiology of ARDS and ALI

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are distinctly modern clinical entities. Recent epidemiologic research has taken advantage of large cohorts in efforts to better describe these highly lethal syndromes with a focus on differentiation of clinically meaningful subtypes and early prediction in an effort to improve treatment and prevention. This article identifies the most significant studies and systematic reviews of recent years, defining the incidence, mortality, risk and prognostic factors, and etiologic classes of ARDS/ALI.

Impact of the A (H1N1) pandemic influenza (season 2009-2010) on patients with cystic fibrosis

BACKGROUND

Influenza, like other respiratory viral infections, can cause acute deterioration of lung function in patients with cystic fibrosis (CF). Previous studies on a small number of patients reported that most people with CF infected with A (H1N1) influenza experienced a mild course of disease.

AIM

To characterise the impact of A (H1N1) infection on CF in a large number of patients from different centres and countries.

METHODS

CF centres accessing the web-site of the European Cystic Fibrosis Society (ECFS) were asked to report clinical data on patients with an ascertained diagnosis of influenza caused by the A (H1N1) virus. The study was web-based and data were collected through an electronic data sheet on the ECFS website.

RESULTS

Twenty-five centres from 10 countries caring for 4698 patients with CF reported data on 110 patients (2.3%), median age 13 years (range 1-39 years). The prevalence of infection in each centre ranged from 0% to 9.4%. Only 8.8% of the patients had been vaccinated. The main symptoms were fever and respiratory exacerbation requiring IV antibiotics in 53% of the patients; 48% of the patients were hospitalised for an average of 12.9 days (range 2-56) and 31% required oxygen treatment during the time of the infection. Most of the patients recovered and FEV(1) 1 month after the infection was similar to that before the infection. However, 6 patients were admitted to ICU, 5 with mechanical ventilation. Three patients with severe respiratory disease died.

CONCLUSIONS

A (H1N1) influenza infection caused transient but significant morbidity in most of the patients with CF. However, in a small number of patients with severe lung disease, A (H1N1) influenza was associated with respiratory deterioration, mechanical ventilation and even death.

CD8+ T cell immunity to 2009 pandemic and seasonal H1N1 influenza viruses

A novel strain of H1N1 influenza A virus (pH1N1) emerged in 2009, causing a worldwide pandemic. Several studies suggest that this virus is antigenically more closely related to human influenza viruses that circulated prior to 1957 than viruses of more recent seasonal influenza varieties. The extent to which individuals who are naïve to the 2009 pH1N1 virus carry cross-reactive CD8+ T cells is not known, but a certain degree of reactivity would be expected since there is substantial conservation among the internal proteins of the virus. In the present study, we examined the production of multiple cytokines in response to virus from CD8+ T cells in healthy adult subjects, between 18 and 50 years of age (born post 1957), who had no evidence of exposure to the 2009 pH1N1 virus, and had blood collected prior to the emergence of the pandemic in April of 2009. Human peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with a panel of live viruses, and assayed by intracellular cytokine staining and flow cytometry. Although results were variable, most subjects exhibited cytokine positive CD8+ T cells in response to pH1N1. Cytokine producing cells were predominantly single positive (IL2, IFNγ, or TNFα); triple-cytokine producing cells were relatively rare. This result suggests that although many adults carry cross-reactive T cells against the emergent pandemic virus, these cells are in a functionally limited state, possibly because these subjects have not had recent exposure to either seasonal or pandemic influenza strains.